Daily cloud stats from LUMO ceilometer network

The below summary tables are derived from LUMO ceimometer observations. Currently, the five CL31 sensors of the network are used. Site locations have changed over the years and include KSS45W, RGS, MR, NK, and IMU. The following metrics are used to determine cloud condition for each day since Jan 2010. At least three sensors have to fulfill the respective criteria (or two and no data available for the other sites).

class

critera

clear

cloud cover in any height < 1%

clearABL

cloud cover below 3km < 1%

little

cloud cover in any height < 5%

littleABL

cloud cover below 3km < 5%

clearDay

cloud cover in any height < 1% during daytime

clearDayABL

cloud cover below 3km < 1% during daytime

littleDay

cloud cover in any height < 5% during daytime

littleDayABL

cloud cover below 3km < 5% during daytime

Summary by year

clear

clearABL

little

littleABL

clearDay

clearDayABL

littleDay

littleDayABL

2010

2

8

4

9

1

3

2

2

2011

8

7

0

11

4

4

1

4

2012

12

8

5

5

4

4

2

2

2013

6

4

6

5

3

2

0

1

2014

5

7

5

6

2

0

0

4

2015

4

9

2

4

6

4

2

2

2016

7

12

4

6

0

3

3

2

2017

6

5

3

6

0

0

2

2

total

50

60

29

52

20

20

12

19

Clear days & days with little cloud in London

The below table is constructed with a hierarchy from left to right, i.e. a day fulfilling criteria of a column is only listed if it does not yet appear in a column towards the left.